Malicious RTF — malware analysis report

Static analysis result for SHA-256 e296276573391f4c…

MALICIOUS

RTF

541.0 KB Authoring application: Riched20 6.3.9600 First seen: 2018-06-21
MD5: 725f28d78d3d0c6f614f065bec577bcd SHA-1: 1171d888e5e055d1557c2050b97b8b75f1bd797b SHA-256: e296276573391f4c10cff09f012d9576584313b8b833aceaf88db12f7cf2b6ca
480 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of malicious activity, most critically the exploitation of CVE-2017-11882 through an embedded Equation Editor object. This vulnerability is known to be used for arbitrary code execution. The presence of PE headers in hex data and ClamAV detections for Agent and Dropper families further confirm its malicious nature, suggesting it acts as a dropper for further malicious payloads.

Heuristics 10

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Win.Dropper.Smdd-6956905-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Dropper.Smdd-6956905-0
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Package object class high RTF_OBJCLASS_PACKAGE
    OLE Package object — can wrap arbitrary files
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • OLE object data medium RTF_OBJDATA
    RTF contains 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000ef.bin rtf-objdata-decoded RTF \objdata at offset 0xEF 268519 bytes
SHA-256: 8a01b9ad2d02b266219cbdb061a0703739854b47b54dc586e6351b387a0279e5
Detection
ClamAV: Win.Dropper.Smdd-6956905-0
Obfuscation or payload: likely
Carved artifact entropy is 7.89, consistent with packed or encrypted content.
objdata_01_off0008330c.bin rtf-objdata-decoded RTF \objdata at offset 0x8330C 3980 bytes
SHA-256: 6033a6f346696e6427d1cb49b4f908a514957f2cee708cc87534aabd8f5343ce
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\Server.exe &��D$,f-Q���%
objdata_02_off00085552.bin rtf-objdata-decoded RTF \objdata at offset 0x85552 3546 bytes
SHA-256: 4b45b86a3c31372ff0b8439426f96afcc39a940955c5ffad45fafc003082ed18
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\Server.exe A C